How Do You Introduce a New Fish to the 'MOB'

[ca1ore]

I slavishly QT all my fish, and it is most discouraging to get a new fish through 4-8 weeks of QT disease free and up to weight only to have it beaten to death by the resident 'mob' in the display. This used to happen to me with some regularity until I adopted my current regimen. Haven't lost a new fish to resident aggression now in almost 5 years (have lost them for other reasons though). It's really just four things:

1. Ensure fish is at a healthy weight and eating before attempting to add it to the display; skinny fish and hiding aren't a combination for a good prognosis.
2. Use a socialization box (also called an acclimation box), and keep the fish in it for at least three days even if there is no observed aggression. Longer is fine.
3. Tape a good sized mirror to one end of the tank; in addition to distracting the more aggressive fish, it's quite comical to watch them posture for their reflections.
4. Release the new fish from the box after the lights have gone off and the 'mob' is sleeping.

There's nothing particularly revolutionary about these things; but they have worked really well for me. Doesn't eliminate aggression completely, but it reduces it enough for a positive outcome. Sequence/order of introduction helps in the early stages of a tank; but becomes impractical after that.

Any different or clever things that other folks are doing?

 

[Greenstreet.1]

Only thing I don’t do is the mirror you never know my have to try it one day.

 

[scuzy]

That's how I do it mirrors on both end of tank and social acclimation box.

 

[Hal3134]

Hmm, I've always wondered if mirrors add any value when adding new fish.

I saw a noticable reduction in aggression when I started using my acclimation box. I agree, that 3 days seems to be about right.

 

[Tuffyyyyy]

I do appreciate this. I've been trying to figure out how to add another fish with a bully clown and six line.

 

[lagatbezan]

curious, how does the fish handle being in a small acclimation box for 3 days?

 

[Greenstreet.1]

depending on size the small fish don't mind the big ones be a little upset when they first go in.

 

[ca1ore]

curious, how does the fish handle being in a small acclimation box for 3 days?

It doesn't necessarily have to be small; though I did make my own because the commercially available options at the time were all too small LOL. If a fish is too big for the box, it's also likely to be too big to be bullied.

 

[LobsterOfJustice]

Instead of the acclimation box, I always make sure I have a front to back break in my aquascape so I can slide an eggcrate divider in to keep the bullies away from the new fish. I like this better than the box because it lets the new fish claim some territory in the tank and find some hiding spots in the rockwork for once the divider is removed.